Korean War Refugee — In this file photo dated as of December of 1950 a crowd of South Korean refugees, bundled in cotton padded quilted clothes, try to cross Han River frozen in the severe winder as they hear Communist Chinese forces advance fast toward Seoul. The sole bridge on the Han River, called Indogyo back then, was bombed by the South Korean army at the break of the Korean War (1950-53).

An earlier chapter in our Past &Present series (No. 7) described the important role played by the River Han in the development of Seoul. But the transition from barrier to vital link between the thriving hubs of the city depended on the existence of bridges, and of those, right up to the 19th century, there were practically none.

This article describes the bridge-building activity since then, which has made Korea one of the leading expert counties in bridge construction.

The first bridges across the Han were in fact not fixtures but pontoon arrangements of connecting floating barges across which boards, tree branches, earth and sacking was laid to permit a stable crossing. The earliest of these was moored at the location of today’s Hangang Bridge. It was only when a more substantial arrangement was needed with the advent of railway transportation that the first fixed bridge, made of steel and concrete, was put up at the same place. This was the first Hangang Rail Bridge, it took from 1897 to 1900 to erect and it stood till 1950 when it was blown up to prevent the advancing North Korean army from crossing.

The first bridge for Vehicle and foot traffic was also called the Hangang Bridge and it opened in 1917. It suffered the same fate in 1950. It was not until 1965 that bridge building began in earnest, with the Yangwha Bridge, and by the time the Seoul to Busan Expressway was opened the Hannam Bridge was already ready in 1969. This bridge has been enlarged twice and now carries 12 lanes of motor traffic.

The 1970s and 1980s saw a feverish bout of bridge construction. Perhaps it was too hurried since one, the Haengju bridge, saw one of its suspension towers snap during construction and another, the Seongsu Bridge, which opened in 1980, collapsed in a tragedy in 1994. Yet another accident occurred in May 2001when the crowning olympic flame, crafted in steel, was to be set atop the superstructure of the eponymous Olympic Bridge. The helicopter comissioned to lower this heavy piece of artwork got caught by a crosswind, rotors striking the bridge suspension cables and crashed, fatally injuring the pilot and two others.

Most of the bridges are for road connection but some do combine motor vehicle and rail or subway train crossings, notably Dongho, Dongjak, and Cheongdam.

Today there are 26 bridges crossing the Han between the convergence of the North and South Han rivers and the point where the Imjin River flows into the Han. Recently completed is a crucial bridge which carries the Arex express train link between Seoul Station and Gimpo and Incheon Airports. Yet another will open in 2017 to be called the World Cup bridge.

Without these bridges the gangbuk and Gangnam hubs might as well be two separate cities, as different in style and character as the Paris and London of Charles Dickens' "tale of Two Cities".

but the record breaker, which is not truly a river bridge, is the graceful and elegant Sea bridge which crosses the Han estuary between the Seoul/incheon Airport and the new development area of Songdo City.

The airport, South Korea's biggest and one of the largest air-cargo facilities in the world, opened in 2001on a leveled-out island and had first been connected by only one bridge to the mainland.

The new Incheon Bridge cost 2.45 trillion won ($2.12 billion) and took four years and four months to build. The length of the structure is 21.4 kilometers, with 18.4 kilometers over water.

The roadway rises to a height of 74 meters, a level that allows tall ships to pass beneath the bridge. At that height, the road deck is held up by cables that attach to two Y-shaped pylons that are 230 meters high.

Opened to traffic in October 2009, the bridge shaves the time it takes to drive between downtown Incheon and the airport to about15 minutes from 45 minutes.

The city side of the bridge connects to Songdo City, which is one of the largest real-estate development now under construction in the world.

Alan Timblick serves as President of The Seoul Times. He grew up in England, graduated from Oxford University, and has lived in Seoul for over three decades. A former banker, he also worked for the Korean government as head of Invest Korea and for Seoul City as head of the Seoul Global Center.